"I think it's the right thing for our team, and I've always got to do what's right for our team and for our school," Haden said.

Offensive coordinator Clay Helton will take charge of the Trojans (3-2, 1-2 Pac-12), who have lost two of their last three games. USC visits No. 14 Notre Dame (5-1) on Saturday.

Haden wasn't specific about the reasons for Sarkisian's absence, only saying that "it was very clear to me" that the second-year USC coach was unwell. Haden asked Sarkisian to take a leave during a phone conversation.

Sarkisian publicly apologized before the season after he appeared to be intoxicated while making an unsteady public statement at the Salute to Troy pep rally. He announced he would be getting unspecified treatment, but didn't believe he had a drinking problem, blaming his appearance on combining alcohol and medication.

Sarkisian is 12-6 during his short tenure leading the talented Trojans, who were dropped from the AP Top 25 after losing 17-12 to unranked Washington last Thursday. Sarkisian had been on the road recruiting during the long weekend, but apparently wasn't in condition to lead practice Sunday, according to Haden.

"(It was) clear the team had a great deal of concern about the health of Coach Sarkisian," Haden said. "So did the staff have that concern for him, and it was also very apparent to me in the room of the support that Clay has from our team and his staff."

Helton begins his second stint as USC's interim coach. He led the Trojans to a Las Vegas Bowl victory in 2013, a calendar year in which the Trojans had four different head coaches.

"It's a very unique honor to get it (this way)," Helton said. "Fortunately or unfortunately, I have been in this situation before, and once again am very fortunate to have a group of first-class kids that are very talented and want to do something special here."

Sarkisian, a former BYU quarterback who played in the CFL, was an assistant under Pete Carroll on the Trojans' great teams of the previous decade. Coaching alongside Lane Kiffin, Sarkisian ran USC's offense before getting hired by the University of Washington to take over a winless program in 2009.

Sarkisian rebuilt the Huskies into a regular bowl team, but couldn't lift them among the Pac-12's elite. The Torrance, California, native left Washington to return home after Haden fired Kiffin five games into the 2013 season and then hired Sarkisian over interim coach Ed Orgeron.

Helton coached the Trojans for one game after Orgeron quit in disappointment. Sarkisian kept Helton on his new staff, which includes five coaches who worked with Sarkisian at Washington.

Sarkisian went 9-4 in his first season at USC, losing a handful of big games but showing promise in the final year of the school's NCAA-mandated scholarship restrictions. In the first recruiting cycle after the sanctions ended, Sarkisian and his staff signed the nation's consensus top class last February.

The Trojans were ranked No. 8 in the preseason AP Top 25 and picked to win the Pac-12 in a media poll, but the talent-laden team has been unimpressive since rising to No. 6 in the rankings last month. USC gave up 41 points in its first loss to Stanford last week, and the offense was inept throughout its five-point loss to the Huskies.

"They still have a lot of things out there that we can attain," Helton said of his players. "We have a big game versus Notre Dame this week, the opportunity to still compete for the South championship in the Pac-12, and again, I'm very fortunate to have a group around me as a staff that is as first-class as they get."

The 43-year-old Helton has been on USC's staff since 2010 after spending 10 seasons as an assistant coach at Memphis, most of it under head coach Tommy West. Kiffin hired him to be the Trojans' quarterbacks coach, and he moved up to passing game coordinator in 2012.

Helton made a smooth transition from Kiffin's more pro-style offense to Sarkisian's more up-tempo approach last season, and he took over play-calling duties from Sarkisian this season.

He is the son of Kim Helton, the former University of Houston coach. Clay Helton played quarterback under his father in the 1990s after starting his college career at Auburn.

"We'll take the same approach as we did the last time we were in this," Helton said. "It's all about the kids, and it's all about the Trojan Family. That's it."

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